#gcc -shared -o libmymath.so mymath.c 
gcc -shared -o libmymath.dll mymath.c
# 如果报错如下，说明是编译的linux版本
#D:/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: cannot find -lmymath
#collect2.exe: error: ld returned 1 exit status